It is well-known that the conventional tent for camping is limited to use on the land and has no other purpose. While being erected on the land, it is inevitably troublesome and time-consuming to dig a ditch around the tent so as to prevent water from accumulating. While camping in a mountain area, in case of an accidental flood, the tent as a whole will be inevitably washed away by the terrible swift currents of the flood and a serious accident will happen. In view of these drawbacks of conventional tents, it is highly desirable to improve the tent for camping.